Because the so-called domestic cat is still very wild in its interactions with other cats, harmony between larger groups of even well-cared-for house cats is not assured. One of the most common complaints of my clients is aggressive behaviors between their pets. Such behavior may arise without warning, involving individuals that have previously been compatible. Such irritable or aggressive interactions can occur between same-sex cats or opposite-sex cats, even if they are all spayed or neutered.
While the exact inciting cause of such sudden changes in inter-cat relationships is often unknown, there are usually some key factors that contribute to trouble. The single most important factor is the number of cats in the “territory.” within the home, the territory is that the area among the house itself. If we consider the size of the range of feral communities of cats, it is easy to understand that even sizable homes of 2,000 to 3,000 square feet are not adequate for more than a small number of animals to live in peace. When sizable numbers of cats are confined in a static amount of space and are unable to expand their territory by moving further away from other cats in the group, friction and aggressive behaviors may result. My experience suggests that keeping more than one cat per 500 to 750 square feet of living space will create a kind of territory stress that can cause disharmony among pet cats.
Male and female cats do not live in constant close proximity to each other within the group’s territory in the wild, and forcing them to do so in the limited space of the home environment can create stress. Sometimes, alpha-type females will become aggressive against other younger or less-dominant individuals. Although females do live relatively close together in the wild, their companionship in that situation revolves around bearing and caring for kittens. When spayed females do not share this common focus, the potential for unpredictable irritable interactions between them is very real. Neutered males seem to make the most continuously harmonious companions with one another within the home environment. Nevertheless, even they can become socially aggressive if their environment is too small, they must share the home with too many others, or if the environment is chaotic.
All cats, whether living feral or within the home, are stressed by large-scale changes in their lifestyle. Moving from one home to another, home remodeling that is long term and extensive, the sudden introduction of a new animal or human family members, and similar disruptions to the status quo can ignite considerable disharmony among pet cats that have previously established good living relationships with one another. In the wild setting, a cat colony will naturally maintain as much lifestyle stability as possible, removing any disruptive influences quickly, reestablishing the group’s routine with minimal long-term disruption. In the home environment, cats experiencing chaos do not have this ability to control their own situation. With significant and continued upset to their customary routine, otherwise, peaceful cats may respond with inter-cat aggression and a breakdown of previously perfect litter-box habits.
I am often asked to explain and treat house soiling misbehaviors in my client’s pets. We sometimes find an organic explanation for such a breakdown, that is, a disease process involving the kidneys, bladder, or gastrointestinal tract. All too often, however, the problem stems entirely from an overcrowded and unstable living environment that causes the patient to feel anxious and threatened by the uncertainty of the changed routine. Highly stressed cats will “act out” in such circumstances, attempting to dominate others with whom they may previously have been equals, or establishing control over territory within the house.
Acting-out behaviors often take the form of territory-marking with urine or feces, as a cat attempts to regain some control and safety in its life. Owners may see this behavior as spiteful. Certainly, it is controlling and manipulative, in some sense. The underlying cause, however, is not mean-spiritedness on the part of the cat, but merely an instinctive reaction to the helplessness the animal is experiencing when the environment seems persistently threatening. The cat is simply doing what its wild ancestors have learned to do in such frightening conditions: reasserting its dominance and staking out some space for itself.
When we understand the underlying cause for such bad behaviors, we can understand that the best way to reverse them is to restore the pet’s sense of security and stability. Punishment will not help, it simply makes the cat feel even more insecure. Antidepressant drugs such as Prozac or Buspar may help, but they merely mask the problem, they do not resolve it. Most owners do not want their cats on such medicines for the long term, and rightly so.